Hydraulic jack



R E s U A F P. M

HYDRAULIC JACK Orig inal Filed Nov. 25, 1931 2 Sheets-Sheet l March 19,1935. E, M PFAUSER 1,994,783

I HYDRAUL'I C JACK 2 Sheets Sheet 2 Original 'Filed Nov. 25, 1931Patented Mar. 19, 1935 UNITED STATES HYDRAULIC JACK Edward M. Pfauser,Milwaukee, Wis, assignor v to Blackhawk Manufacturing 00., Milwaukee,

Wis.

PATENT OFFICE,

Application November as, 1931, Serial No. 511,203

Renewed August 2, 1934 .6C'laims.

This invention relates to hydraulic l cks in general, and moreparticularly to what are termed portable or dolly jacks.

tive to the pump operating mechanism, whereby the handle can be operatedin one of several angular positions to allow for restricted operatingspace and maintain the most efllcient operation of the pump mechanism.15

Incidental to the lifting mechanism, a mo e specific object resides inthe provision of a jack comprising a stand having a lifting armpivotally connected thereto adjacent one end and actuated bya'hydrauiic-ram and pump mechanism housed in a unitary casing, pivotallymounted adjacent the same end of the stand, and in close proximity tothe actuating handle, thus providing maximum compactness, high-lift, andelimination of excessively long connecting members and links common topresent conventional types of jacks.

A further object resides in the novel manner of control of the pump,togetherwith adjustment of the operating handle through the handleitself, thus materially facilitating operation of the 30 jack. I

With the above and other objects inview, which will appear as thedescription proceeds, the invention resides in the novel construction,combination and arrangement of parts, substantially as hereinafterdescribed and more particularlydefined by the appended claims, it beingunderstood that such changes in the precise embodi ment of the hereindisclosed invention maybe made as come within the scope of the claims.

In the accompanying drawings is illustrated one complete example of thephysical embodiment of the present invention constructed according .tothe best mode so far-devised for the practical application of theprinciples thereof.

Figure 1 is a plan view of one form of jack' constructed inaccordancewiththe present invention. I

Figure 2 is a longitudinal section taken on the line 2-2 of Figure 1..-

Flgure 3 is a fragmentary plan '01 a modified form-of the invention,parts-being broken away and in section to more clearly illustratestructural features.

Figure 41s a detail fragmentary section taken" ll onthellneHofm iFigures 5 and 6 are diagrammatic illustrations of the operation ofconventional jacks.

While the present invention relates in general to hydraulic jacks ofvarious types, the same has been illustrated in connection with a dollyjack, 5 to which type certain features of the invention are particularlyapplicable. For instance, in dolly jacks, such as illustrated, the jackis generally positioned beneath the vehicle by manipulation of thehandle, and to facilitate such op- -10 eration't-he handle is generallyutilized as a lever to raise the forward end of the jack for shifting,thus permitting the lifting element to be aligned with the desired partof the vehicle. In conventional types of jacks it is necessary to forcethe handle down to its lowermost position in order to effect theforegoing operation, and where the jack is utilized in restrictedspaces, considerable difficulty is encountered. Consequently, adjustability of the present handle with relation to the pump actuatingmechanism allows the handle to be used as a suitable lever in uprightposition necessary to a confined or restricted space. Referring now moreparticularly to that form of' the invention illustrated in Figures 1 and2, the numeral 1 designates generally a frame or stand, comprising apair of side frames 2 connected-at their forward ends by a transverseaxle 3, having mounted thereon the supporting wheels or rollers 4.Carried at the rear ends of the side frames 2 is a pair of opposed stubshafts 5, hav- 'ing mounted on their outer ends rear supporting rollers6, while secured'to-their inner ends is a. yoke '7, to which is securedin any suitable man- 7 ner a tubular operating handle 8. As-best shownin Figure 1, a transverse shaft 9' connects the side frames adjacenttheir rear end and has pivotally mounted thereon a lifting arm 9provided at its outer end with a pivotal shoe 10 for engagement with theload to be raised. The shoe 40 10 is provided with a depending tailpiece 11, connected with the side frames 2 by the links 12, pivotallysecured to the inner faces of the side. frames by the studs 13.

Thea'ctuating mechanism for operation of the ,45

high. lift of the shoe 10 upon comparatively limited movement of the ram14. Obviously, as the ram is actuated to raise or lower the arm 9, piv-Otal action of the casing 16 will compensate for the arcuate movement ofthe arm 9 to which the ram is connected, as heretofore explained.

To effect operation of the pump plunger 15 to create hydraulic pressureupon the ram in the conventional manner, the casing 16 is provided witha bearing 19 having joumaled therein a rocking shaft 20. Secured on theshaft 20, adjacent the plunger 15, is a pair of spaced arms 21 whichstraddle the plunger 15 and carry a stud 22 which is engaged in thebifurcated end of the plunger 15, as best shown in Figure 2. On one endof the rocking shaft 20 an arm 23 is secured, which arm is connectedwith an offset arm 24, carried by the yoke 7, by means of a link 25.Thus, as the handle 8 is oscillated, oscillatory movement is transmittedthrough the link 25 to the rocker shaft 20, causing the plunger to bevertically reciprocated.

Obviously, as the casing 16 rotates on the studs 17, during theoperation of the arm 9, the slight relative movement occurring betweenthe casing and yoke is largely compensated for through the linkconnection 25, thus having no appreciable effect upon operation of thepump mechanism.

Control of the hydraulic pressure, which actuates the arm, is obtainedby a conventional release valve 26 threaded into the casing 16 adjacentits rear end. When the valve is open the lifting arm is returned to itslowermost position by means of either the load carried on the shoe 10,or, when the load has been removed, by the spring 27 connecting one ofthe links 12 with the adjacent side frame 2.

To facilitate actuating of the release valve 26, the same is connectedwith the rod 28 by the universal coupling 29. The rod 28 projectsthrough the tubular handle 8 and has secured to 1 its upper end a handgrip 30 which is rotatably carried by the handle 8. Thus, in order toeffect complete operation of the jack, it is merely necessary to graspthe grip 30 and rotate the same to close the release valve 26, afterwhich the handle 8 is oscillated to actuate the pump mechanism forraising the ram 14, causing the 'arm 9 and lifting shoe to be raised.Then, without performing any other operation than to rotate the grip 30to open the valve 26, the load is lowered.

As previously set forth in the objects of the invention, and in thespecification, it is frequently necessary to operate a jack inrestricted space, due to the close proximity of various obstructions.This is particularly dimcult in connection with dolly jacks, and becauseof the relative size of jacks of this type, it is often impossible toeffect normal actuation of the pump mechanism.

Instead, the restricted space permits only a very limited manipulationof the handle over an inefficient arc, resulting in prolonged, tediousoperation in order to actuate the jack.

To overcome the foregoing, the present invention provides adjustmentbetween the operating handle and the pump actuating mechanism,

2 which permits the handle'to be adjusted to one of a plurality ofoperative positions without in any way afiecting the mostefficientactuation of the pump mechanism. To accomplish this the modificationillustrated in Figures 3 and 4 utilizes a yoke 7 secured on the stubshafts 5, similar to the yoke 7. However, the yoke '7' is plained,serves to operate the pump. The arcuate face of the detent 31 isprovided with a plurality of-recesses 32 for reception of a springurgedlocking pin 33 carried by the yoke 7. For manipulating the pin 33 toeffect adjustment of the yoke '7 with relation to the detent, areciprocal rod 34 is carried by the yoke and the handle 35, which issecured to the outer end of the tubular member 8. A trigger 36 securedto the rod and projecting through the handle permits actu-' ating of therod 34, one end of which engages the pin 33 to withdraw the same fromthe detent when adjustment is' desired. Manipulation of the releasevalve 26 is obtained in the same manner as described in connection withthe other form of the invention. In this instance the knob 30',rotatably mounted on the handle 35, serves to oscillate the rod 28.

From the foregoing explanation, taken in connection with theaccompanying drawings, it will .be readily apparent that an extremelysimple,

compact and durable jack' structure has been provided, which presentsnumerous advantages over conventional types of jacks, in that a minimumnumber of parts are required, which .parts are so assembled withrelation to each other as to provide an exceedingly high lift throughrelatively limited actuation of the operating mechaof conventional jacksas compared with the present jack.

For instance, where the operating handle or yoke 7 is rigidly connectedwith the arm 24, the arm 24 can only be operated through its mostefficient arc, as illustrated in Figure 5, when the handle is oscillatedthrough a corresponding arc. In the position shown, naturally the lengthof movement transmitted to the connecting link 25, and designated by theletter :0, is the maximum. Assuming then that because of a restrictedspace within which to'operate the handle it is necessary to raise thesame, necessarily the arm 24 must be lowered, as illustrated in Figure5, thus causing the same to be oscillated through an arc that impartsonly limited movement to the link 25, as designated by the letter y,which is materially less than-the distance .r. Obviously, such actuationof the pump mechanism materially prolongs the lifting operation. This isentirely overcome by the adjustable handle disclosed in Figures 3 and 4,which allows the handle to be set at any one of a plurality of operativepositions without aflecting the position of the arm 24, thus maintainingthe most efficient action of the pump actuating means, and permittingthe handle to be used as a lever in one of several positions, for thepurcilitate lateralshifting of the same.

til

I claim:-

1. A hydraulic jack comprising a pair of side frames, a transverse shaftconnecting the forward ends of said side frames, supporting wheelsmounted on said shaft, a normally horizontal lifting arm pivotallymounted between said side frames adjacent their top and rear ends, acasing positioned between said side frames and pivotally connectedthereto, the pivotal axis of said casing being below the pivotal axis ofsaid lifting arm and adjacent the rear ends of said side frames, a ramvertically operable in said casing and pivotally connected to saidlifting arm. closely adjacent its pivotal axis, a. pump operable in saidcasing for actuating said ram, alined spaced shafts carried by the sideframes at their rear ends, supporting wheels mounted on said shafts, ayoke pivotally mounted on said shafts, means operatively connecting saidyoke and pump, and a handle carried by said yoke for oscillating thesame.

2. A hydraulic jack comprising a stand, a normally horizontal liftingarm pivotally connected to said stand adjacent its top, a casingpivotally connected to said stand adjacent its bottom portion and belowthe connection of said lifting arm, a ram vertically operable in saidcasing and pivotally connected directly to said arm closely adjacent itspivotal connection and in substantially horizontal alinement with thesame, a pump positioned forwardly of said ram in said casing foractuating the ram, an oscillatory handle pivotally connected to saidstand closely adjacent the rear of said casing, and means operablyconnecting said handle and pump.

3. In a lifting jack of the class described, a main frame, an operatinglever pivoted onthe frame, said lever providing a handle arm and aworking arm, a lifting arm pivoted on said frame,

a hydraulicframe pivoted on said main frame,

said hydraulic frame comprising a jack cylinder having a ram guidedtherein, the ram being pivoted to the lifting arm wherebysaid hydraulicframe swings about its pivot as the lifting arm is raised or lowered, apump carried by the hy draulic frame, said pump having a cylinder and aplunger, a pump operating lever for actuating the pump plunger, saidlatter lever having a journal rigid with the hydraulic frame and havinga working arm, said working arms in their mean positions being disposedapproximately parallel with each other, and a link pivotally connectingsaid working arms, angular movement of said hydraulic frame about itspivot changing the mean position of one of said arms with respect to theother.

4. In a lifting jack of the class described, a main frame, an operatinglever pivoted on the frame, said lever providing a handle arm and aworking arm, a lifting arm pivoted on said frame, a hydraulic framepivoted on said main frame, said hydraulic frame comprising a jackcylinder having a ram guided therein, the ram being pivoted to thelifting arm whereby said hydraulic frame swings about its pivot as thelifting arm is raised or lowered, a pump car-. ried by the hydraulicframe, said pump having a cylinder and a plunger, a pump operating'leverfor actuating the pump plunger, said latter lever having a journal rigidwith the hydraulic.

frame and having a working arm, said working arms in their meanpositions being disposed approximately parallel with each other, and alink pivotally connecting said working arms, angular movement of saidhydraulic frame about its pivot changing the mean position of one ofsaid arms with respect to'the other, and means for adjusting the angularposition of the handle arm with respect to the working arm of theoperating lever to compensate for the changed'angular relation of saidone working arm with respect to the other.

5. In a lifting jack of the class described, a main frame, an operatingbell crank lever pivoted on said frame and comprising a handle arm and aworking arm, the mean position of the working arm being substantiallyvertical, a lifting arm pivoted on the frame,'a hydraulic frame pivotedon said main frame, said hydraulic frame comprising a jack cylinderhaving a ram guided therein, the ram being pivotally connected to thelifting arm whereby said hydraulic frame swings about its pivot as theposition of the lift ing arm is changed, a pump carried by the hydraulicframe, said pump comprising a cylinder and a plunger therefor, a pumpoperating bell oted on said frame and comprising a handle arm and aworking arm, the mean position of the working arm being substantiallyvertical, 9, lifting arm pivoted on the frame, a hydraulic frame pivotedon said main frame, said hydraulic frame comprising a jack cylinderhaving a ram guided therein, the ram being pivotally connected to thelifting arm whereby said hydraulic frame swings about its pivot as theposition of the lift-- ing arm is changed, a pump carried by thehydraulic frame, said pump comprising a cylinder anda plunger therefor,a pump operating bell crank lever for actuating the plunger, said leverhaving a journal rigid with the hydraulic frame, and having a workingarm, the mean position of which is substantially vertical, and a linkconnecting said working arms, and means for adjusting the angularrelation between the handle arm and the working arm of the operatinglever to compensate for the change in the' mean position of one of saidworking arms with respect to the other.

EDWARD M. PF'AUSER,

